The Obama administration's release Monday of proposed regulations for about 600 coal-burning power plants puts the black rock at the center of the race between Republican U.S. Sen. Mitch McConnell and Democrat Alison Lundergan Grimes.

And the new regulations couldn't have come at a worse time for Grimes, said Stephen Voss, a political science professor at the University of Kentucky.

The fact that many people believed that former U.S. Rep. Ben Chandler, D-6th District, lost his House seat two years ago because of the coal issue means that McConnell will focus on it against Grimes in 2014, he said.

"Until these regulations came out, it wasn't necessarily clear that their emphasis on it would be justified," Voss said. "I mean there really wasn't a coal issue that could become the focal point of the campaign, but the issuance of new regs allows it to be that focal point."

Both McConnell and Grimes, Kentucky's secretary of state, issued statements saying the rules are examples of government overreach and promised to fight them, even as Grimes has said she believes humans are at least partly to blame for climate change and the issue needs to be addressed.

McConnell, who has made it clear that he plans to run in large part on the Obama administration's stance on coal, said in a release that the proposed rules are "a dagger in the heart of the American middle class, and to representative Democracy itself."

In a news conference at Louisville International Airport, the Senate minority leader said any attempt to further control carbon emissions "has to be done on a global basis."

He said increased emissions by China and India will more than offset the reductions Obama is seeking. "This will be a body blow to Kentucky's economy."

The U.S. power sector must cut carbon dioxide emissions 30 percent by 2030 from 2005 levels, according to federal regulations unveiled on Monday. Rough Cut (no reporter narration).

Grimes, who has tried to portray herself as a friend of coal despite McConnell's assertions otherwise and has criticized Obama's coal policies, said in her release that the proposed rules are "more proof that Washington isn't working for Kentucky."

"Coal keeps the lights on in the Commonwealth, providing a way for thousands of Kentuckians to put food on their tables," said Grimes, who, in accepting her party's nomination two weeks ago, used McConnell's words and accused Obama of waging a "war on coal."

"When I'm in the U.S. Senate, I will fiercely oppose the president's attack on Kentucky's coal industry because protecting our jobs will be my number one priority," she said Monday.

Her campaign also announced that it will begin running full-page ads in Eastern and Western Kentucky newspapers that address the new regulations, saying "President Obama and Washington don't get it ... Alison Grimes does."

She has said the nation should focus on carbon sequestration as a way to trap greenhouse gases.

McConnell also has campaigned on the possibility that Grimes would vote to re-elect U.S. Sen. Harry Reid, D-Nev., as Senate majority leader. At virtually every campaign stop he makes, McConnell points out that Reid in 2008 said that "coal makes us sick" while advocating for advancements in alternative forms of energy during a spike in oil prices.

McConnell noted Monday that he would propose an amendment that would block the proposed regulation but that it's up to Reid to determine if there is a vote on the measure.

Grimes has not committed to voting for Reid.

Meanwhile, the two campaigns spent the day targeting each other for ties to anti-coal positions, including the fact that Grimes is scheduled to attend a fundraiser this week where Reid will work to bring in contributions for her campaign.

The Grimes campaign noted that McConnell has received more than $6,000 from people who have made anti-coal statements in the past and circulated a story about U.S. Sen. Rand Paul, who is backing McConnell, having said in 2008, "coal power is a very dirty form of energy. It's probably one of the least favorable forms of energy."

But Grimes has accepted money from more people who believe that global climate change is the fault of humans and favor restrictions to limit the amount of carbon emissions.

Jennifer Duffy, a senior editor at the nonpartisan Cook Political Report in Washington, said the new rules make it difficult for Grimes in a state that mines and burns coal like Kentucky does. "It's hard, but I'm not sure I'm going to call it devastating," she said. "But (Grimes) has done things that don't make it easier on her, like some of the people that she's taken money from."

Duffy said Democrats tried to persuade Obama to delay issuing the proposed regulations because many of the Senate seats where Democrats are battling in hopes of holding on to the Senate majority are in states seen as friendly to coal and other fossil fuels, including Kentucky, West Virginia, North Carolina and Louisiana.

"The fear is driven not as much by the regulations but where the races are," she said. "They are in a lot of the states that depend on coal or have coal-fired plants."

Reporter Joseph Gerth can be reached at (502) 582-4702. Follow him on Twitter at @Joe_Gerth.